    :lb_port (or lb_port port)
    :lb_protocol (or lb_protocol protocol)})
 
-(def default-number-of-master-instances 3)
-
 
 (defn cluster-infra
   [{:keys [vpc-name

                               :exhibitor-s3-bucket (cluster-unique "exhibitor-s3-bucket")
                               :internal-lb-dns (cluster-output-of "aws_elb" "InternalMasterLoadBalancer" "dns_name")
                               :fallback-dns (vpc/fallback-dns vpc/vpc-cidr-block)
                               :number-of-masters default-number-of-master-instances}
                        })

             (asg "MasterServerGroup"

                               :exhibitor-s3-bucket (cluster-unique "exhibitor-s3-bucket")
                               :internal-lb-dns (cluster-output-of "aws_elb" "InternalMasterLoadBalancer" "dns_name")
                               :fallback-dns (vpc/fallback-dns vpc/vpc-cidr-block)
                               :number-of-masters min-number-of-masters}})

             (asg "PublicSlaveServerGroup"
                  cluster-unique
